1. Field of the Invention
This invention relates generally to the field of development of fish friendly hydraulic systems, and more specifically, relates to a bio-hydraulic testing system for simulating flow conditions within a hydraulic system to test the effect on fish of specific hydraulic components and flow conditions.
2. Related Art
There is an increasing concern with increasing the survivability rate of fish as they pass through hydro power turbines and other passage obstructing structures. To fulfill this need, an improved knowledge of biological and engineering design criteria are required to make hydraulic structures more fish friendly.
As water flows through a hydroelectric power generation plant, over a dam spillway, or about other hydraulic systems, it undergoes numerous changes. These changes result from changes in the dimensions of flow boundary, changes in flow velocities, changing energy forms, and changes resulting from other forces acting on the flow. Objects within the flow, such as fish, affect and are affected by these changes, and some of these changes are harmful.
Specifically, when hydroelectric power installations are operated, a large number of fish typically pass through the hydroelectric turbines. Some of the passing fish suffer injuries caused by contact with fixed of moving machinery within the installation, changes of pressure or turbulence effects.
A number of fish injuries occur because the physical changes within a hydraulic system are translated into hydraulic phenomena which are harmful to fish. These phenomena include turbulence, shear stress, cavitation, and pressure fluctuations. Shear stress results from the movement of two adjacent fluid bodies in different, usually opposite, directions. Hydraulic shear has been widely cited as a source of damage to fish in hydraulic turbines. Cavitation is the formation of a partial vacuum in flowing water. Collapse of the vacuum disturbs water flow resulting in injury to fish.
The hydroelectric power generating community as well as resource agencies are actively looking for ways to reduce the adverse effects that hydroelectric generation plants have on migratory fish. Government as well as private groups are pursuing the development of conceptual designs of xe2x80x9cfish friendlyxe2x80x9d turbines. To meet current environmental design criteria, turbines need to be made more fish friendly and environmentally friendly, and yet continue to efficiently provide power.
Additionally, fish are likely to be damaged by abrasion, strike and grinding injuries. These injuries result from sudden changes in flow direction and boundary dimensions, combined with the presence of structures in the path of the fish. Abrasion damage occurs when a fish rubs against a turbine system component or other object in a flow field. Grinding injuries occur when fish are drawn into gaps of a size close to that of the fish within a hydraulic system. A precise prediction of injury due to abrasion and grinding is not currently possible. Injury to a fish due a collision, or xe2x80x9cstrike,xe2x80x9d occurs when a fish collides with a stationary or moving object within the turbine system. The probability of a fish dying from striking an object within the turbine system is variable and not clearly understood. Direct visual observations are not available to correlate mortality to strike, and to verify existing strike probability models.
There is significant literature concerning injury to fish resulting from contact with hydraulic systems. However, surprisingly little is known about the effects of individual hydraulic components on fish or the effects brought about by design changes to individual components.
Development of fish friendly hydraulic systems, such as turbines, spillways, and fishways requires the presence of reliable basic engineering and biological design data. This data includes quantitative estimations of injury mechanisms to fish as they pass through these systems. At present, there is no known testing apparatus in the field capable of replicating flow conditions similar to those encountered by fish on their migratory route.
A bio-hydraulic testing system is provided for simulating the effect on fish of at least one hydraulic system component. In a preferred embodiment, the system comprises: a water flow introduction means; a fish introduction system means; a flow introduction conduit including an entrance end in communication with the fish introduction means and the water flow introduction means so as to receive a water flow containing fish and further including an exit end; a testing module, connected to the exit end of the flow introduction conduit so as to receive said water flow; monitoring means for monitoring and recording fish activity in the water flow in the testing module; a flow exit conduit including an entrance end connected to the testing module and an exit end; a fish collection means located downstream of the exit end of the exit conduit for collecting fish exiting from the testing module; and discharge means for discharging the water from the testing system.
Preferably, the water flow introduction means comprises a headpond for containing water, and means for reducing flow turbulence within the headpond; and the water introduction means comprises an inlet pipe, in fluid communication with the headpond, for introducing water to the headpond.
Advantageously, the fish introduction system comprises a tank for holding fish until introduction thereof, an injection pipe, connected at one end to the tank and having an opposite end dispersed in proximity to the introduction conduit, for transferring fish from the fish tank to the entrance conduit, and a slide gate mounted on the injection pipe for controlling introduction of the fish to the introduction conduit.
Alternatively, the water flow introduction means preferably comprises an inlet pipe connected to the introduction conduit, and the fish introduction means comprises inlet means for introducing the fish directly into the inlet pipe. Advantageously, the inlet means for introducing the fish directly into the inlet pipe comprise a fish introduction member connected to the inlet pipe at a non-perpendicular angle to the inlet pipe for introducing fish into the inlet pipe, and a slide gate mounted on the fish introduction member for controlling the introduction of fish.
Preferably, the introduction conduit is tapered inwardly from the entrance end to the exit end, and the exit conduit is tapered outwardly from the entrance end towards the exit end.
Advantageously, at least part of the entrance conduit comprises a light transparent material for enabling visual monitoring of fish.
Preferably, at least part of the testing module comprises a light transparent material for enabling viewing of at least part of the interior of the testing module from outside the module.
Advantageously, the monitoring system comprises a video camera for capturing images from the testing module, and means for controlling the video camera. Alternatively, the monitoring means preferably comprises a plurality of tags adapted for attachment to a plurality of fish, and at least one antenna, disposed in proximity to the testing module, for receiving at least one signal from the plurality of tags.
Preferably, the material comprising the light transparent part of the testing module comprises one of a clear acrylic material and a clear plexiglass material.
Advantageously, the testing module comprises at least one wicket gate attached to an end of the testing module.
Preferably, the testing module comprises at least one turning vane disposed within the testing module. Advantageously, the at least one turning vane comprises a pair of turning vanes disposed in alignment to each other relative to the direction of water flow through the testing module. Alternatively, the at least one turning vane preferably comprise a pair of turning vanes disposed in a non-aligned relation to each other relative to the direction of water flow through the testing module.
Preferably, the testing module comprises a cavitation element disposed within the testing module for producing cavitation therein.
Advantageously, the testing module comprises a turbine blade element for reproducing conditions in proximity to a turbine, and means for adjusting the turbine blade element to control blade speed, blade tilt, blade shape, and the number of turbine blades.
Preferably, the testing module comprises a testing element disposed within the testing module, and means attached to the testing element for adjusting the orientation of the testing element within the module.
Advantageously, the fish collection means comprises: transfer means disposed in proximity to the exit end of the exit conduit for transferring fish from the exit conduit; a screen located in proximity to the transfer means for separating the fish from the water flow, so that fish are transferred from the exit conduit to the screen by the transfer means; and a collection trough, disposed adjacent to the screen, for collecting fish. Preferably, the transfer means comprises a pair of guide walls, each guide wall being disposed at one end in proximity to the exit end of the exit conduit and at the opposite end in proximity to the screen.
In addition, a method is provided for simulating the effect on fish of a hydraulic system component using a bio-hydraulic testing system, the method comprising the steps of: introducing a flow of water to the testing system; introducing a plurality of fish into the testing system within the flow of water; directing the flow of water with the fish therein into a testing module; simulating the effect on the fish of at least one hydraulic system component within the testing module; monitoring and recording fish activity within the testing module during the stimulating step; and transferring the fish from the testing module to a fish collection means for collection.
The testing system of the invention isolates hydraulic components and phenomena and allows study of the effects of each so as to understand and predict the effects of each upon fish. This testing facilitates improved design for such components. Improvements of such individual components result in safer passage for fish.
Other features and advantages of the invention will be set forth in, or will be apparent from, the detailed description of the preferred embodiments which follows.